Control of plasmonic fluorescence enhancement on self-assembled 2-D colloidal crystals

Abstract

Ordered arrays of Ag-capped colloidal crystals were fabricated and modified with conjugated polymers to evaluate the excitation and emission fluorescence enhancement due to localized surface plasmon resonance (LSPR). The maximum enhancement accrued on the maximum overlap between the excitation wavelength and LSPRs of the substrates. The observed fluorescence enhancement and lifetime measurement showed that the large enhancement came from a combination of greatly enhanced excitation and an increased radiative decay rate, leading to an associated enhancement of the quantum efficiency. Thus, such Ag nanostructured arrays fabricated by colloidal lithograph show great potential for biosensing and photovoltaic applications, and the excitation wavelength–LSPR-based fluorescence enhancement proves useful for understanding and optimizing metal-enhanced fluorescence.